Plastic wax board liner



Patented July 31, 1934 UNITED STATES PATENT orrica Hazel-Atlas Glass 00.,

Wheeling, W. Va... a corporation of West Virginia No Drawing. Appli cation June 10, 1930,

Serial No. 460,298

2 Claim.

This invention relates to liners for bottle and jar closures and has special reference to liners which are commonly known to the trade as a plastic wax board liner.

Liners of this type are highly desirable for the packaging of certain classes of goods in glass containers, but as now constructed are comparatively expensive in that the wax coating comprises, among other constituents, ceresin and bees wax. It is the primary object of the present invention therefore, to provide a wax board liner of low cost and yet which will have all of the salient features of the more expensive liner.

I have found from a long series of experiments that when crude rubber is dissolved in molten paraffin wax for a short time at low temperature, a viscous mixture results, which when applied to pulp board or the like, and cooled, provides an excellent wax board liner.

The experimentation has been carried out with a variety of grades of crude rubber, and while practically all are found to be suitable for dissolving in par and for imparting the desired plasticity to the resulting mixture, best results have been obtained when using pale crepe plantation rubber of a type having a minimum amount oi the rubber odor. Various percentages of crude rubber and paraiiin have been tested, and while plastic compositions of good quality have resulted in most instances, it is found that a compound containing 12% to 14% of crude rubber by weight and about 88% to 86% of paramn is the most desirable in practice.

In manufacturing the improved liner the paraiiln is first melted and the desired percentage of rubber (preferably pale crepe plantation rubber) added. The temperature at which the paramn is melted should be maintained as low as possible and only for such length of time as is necessary to obtain a complete solution of the rubber. This is of paramount importance for the reason that it has been found that prolonged heating of the mixture, or too high temperatures. results in a lowering of the viscosity of the mixture. Whereas a mixture fairly high viscosity is desirable for use as a coating for liners; otherwise the mixture will impregnate the pulp board, with a consequent increase in the cost of manufacture.

The pulp board or other material employed as a base for the liners is coated with the comparatively thick and viscous mixture of parafiin and rubber, by dipping or otherwise, and the coated material is then allowed to cool or may be cooled artificially. A uniform and unbroken film of the wax mixture is thus formed on the board; and to complete the liner it is only necessary that discs of the desired diameter be stamped out in the usual way.

Liners of pulp board or the like, coated with a wax-rubber mixture as above described, are found to be highly efficient in use, are practically free from objectionable odor, and are, of course, considerably cheaper to manufacture than the wax board liners now in use.

While in describing the invention I have referred specifically to pulp board and paramn, it is to be understood that other waxes may be substituted for paraflin in the mixture and that other material such as paper or the like, may be used v in lieu of pulp board.

In accordance with the patent statutes I have described what I now believe to be the preferred form of the invention, but the percentages of materials used in the mixture as well as the manner of its preparation and application may vary considerably, and all such variations are intended to be included within the scope of the appended claims.

What I claim is:

1. A liner for jar closures comprising a body of pulp board, said body coated with a plastic mixture composed of approximately 88% paraflin and approximately 12% rubber.

2. A liner for jar closures comprising a body of pulp board, said body coated with an unbroken 96 film of a plastic mixture composed of approximately 88% paraflin and approximately 12% pale crepe plantation rubber.

DANIEL M. GRAY. 

